Method and apparatus for forwarding twisted yarns

ABSTRACT

APPARATUS AND METHOD FOR FORWARDING A NON-CIRCULAR, CONTINUOUS STRAND, TOW OR YARN HAVING A SLIGHT TWIST IMPARTED THERETO BY GUIDING THE YARN TO A FORWARDING ZONE AND NIPPING THE YARN INTERMITTENTLY BETWEEN A TANGENTIALLY ENGAGING, STRIATED ROLL ASSEMBLY WHICH PERMITS THE YARN TO BE FORWARDED WITH THE TWIST INTACT.

1971 R. CONSTANTAKIS 3,626,635

METHOD AND APPARATUS FOR FORWARDING TWISTED YARNS Filed Jan. 30, 1970 INVENTOR. ROBERTO CONSTANTAKIS AGENT United States Patent O1 hoe 3,626,685 Patented Dec. 14, 1971 US. Cl. 57-156 3 Claims ABSTRACT OF THE DISCLOSURE Apparatus and method for forwarding a non-circular, continuous strand, tow or yarn having a slight twist imparted thereto by guiding the yarn to a forwarding zone and nipping the yarn intermittently between a tangentially engaging, striated roll assembly which permits the yarn to be forwarded with the twist intact.

Background of the invention A first step in textile winding, draw-winding, and drawtwisting operations utilizing continuous yarns, such as of nylon and polyester structure, is the removal or withdrawal of the yarns from packaged supply bobbins of spun yarn. conventionally, the supply packages are mounted on creels positioned to provide an over the end take-off of a yarn from a respective bobbin purposely to impart a slight twist to the yarn. The twist acts to hold the separate filaments of the yarn bundle together. The yarn is guided from the supply package to a traverse guide and then into the bight or nip between a pair of surface engaging rolls of a feed roll assembly including a driven feed roll and an idling cot roll. conventionally, feed and cot rolls are smooth surfaced rolls suited for forwarding yarns of circular crosssection having an over the end twist applied thereto. Generally, no problems are encountered by the twist applied to the yarn. However, in attempting to process a non-circular yarn such as a flat, ribbon-like yarn in the conventional manner, the twist generated in a flat yarn does not readily pass through the nip of the smooth surfaced, feed-cot roll assembly. Instead, the twist is stripped back toward the supply package and accumulates to form a highly twisted segment that slowly forces itself between the feed and cot rolls at irregular intervals. The result is a sub-standard and an undesirable textile operation. The present invention permits the processing of non-circular yarns by an over the end take-01f from a supply package and a forwarding thereof by a striated feed roll assembly without backing up of the twist.

SUMMARY OF THE INVENTION The invention comprises the combination of a source of supply of non-circular yarn, a guide positioned to guide the yarn in an over the end withdrawal from the supply package to a forwarding zone resulting in a slight twist being developed in the yarn, and a feed roll assembly including a pair of surfacely engaging rolls in the forwarding zone. One of the feed rolls is a driven roll and the other is an idle roll having transverse grooves adapted to permit passage of twisted, non-circular yarn therethrough.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is an elevation view, in perspective, illustrating one embodiment of the apparatus and method of the invention,

FIG. 2 is a perspective view showing another embodiment of the feed roll assembly of the invention,

FIG. 3 is a perspective view illustrating a length of noncircular flat, twisted multifilament yarn with the filaments bonded together, and

FIG. 4 is a perspective view illustrating a twisted, ribbon type monofilament yarn.

DESCRIPTION OF PREFERRED EMBODIMENTS In the following description, like components in the several figures of the drawing are identified by like reference numerals.

FIG. 1 illustrates the method and apparatus of the invention for forwarding a non-circular yarn, particularly a fiat, twisted yarn, in a yarn drawing or stretching operation. A yarn 2 is shown being withdrawn over the end of a supply package 4, then extending through. a pigtail guide 6 and downwardly through a slot of a reciprocable traverse guide 8, passing through the nip of a feed roll assembly .10 driven at a preselected peripheral rate of speed, and extending therefrom around a draw roll assembly 12 driven at a faster rate of speed to stretch the yarn therebetween.

The feed roll assembly 10 comprises a feed roll 14 driven by a motor 16 and a surface engaging, pivotal cot roll 18. The cot roll 18 has a plurality of uniformly spaced teeth 20 with striations or grooves 22 therebetween. Preferably, teeth 20 extend transversely, axially across roll 18, FIG. 1. However, other angular or diagonal configurations of teeth 20 may be used as illustrated in FIG. 2. Preferably, the cot roll 18 is made of a resilient material and the teeth 20 are square to provide fiat lands 24 that will make more surface contact with the yarn than a sharp tooth. Grooves 22 should have a width and depth dimension to prevent a continuous nip being taken of the yarn as it passes between the feed and cot roll. Where the cot roll 18 is resilient, the compressibility of the material used should be taken into account to assure that the resilient material does not flatten when engaging the feed roll to the extent that there is no gap for the yarn to stretch across as it passes between the rolls.

The draw roll assembly 12 comprises a draw roll 26 driven by a motor 28, and a spaced separator roll 30.

FIGS. 3 and 4 illustrate two different non-circular ribbon-type yarns 26 and 28, respectively, that are readily processable by the method of the invention. Yarn 32 is a multifilament, flat yarn having the filaments bonded together, and yarn 34 is a fiat, monofilament yarn. A flat yarn may be described as one having flat, opposed sides of a width greater than the thickness of the yarn.

In operation, the yarn 2 after being withdrawn over the end of package 4 and laced through guides 6 and 8 and having a twist imparted thereto, is laced around the cot roll 18 before passing through the nip between the feed and cot rolls. From the feed roll assembly 10 the yarn extends around the separator roll 30 and draw roll 26 which impart a stretch to the yarn. When the feed and draw roll assemblies are driven, the yarn 2 intermittently nipped by successive tooth engagement of the cot roll 18 with the feed roll 14. The twist in the yarn does not back up toward the yarn package 4 because the grooves 22 permit the twist in the yarn 2 to be forwarded in situ with the yarn. In the illustration, the yarn 2 is forwarded to a draw roll assembly 12.

The process and apparatus are particularly suited to processsing a multifilament, flat yarn, as shown in FIG. 3, wherein the diameter of the separate filaments is from 10-100 microns and 7-34 filaments are bonded in a sideby-side horizontal arrangement.

Although the cot roll 18 is illustrated as the grooved roll, it will be understood that the feed roll 14 instead of the cot roll 18 may be grooved, in which case the cot roll 18 will be smooth roll. The invention, by illustration, is ap plied in a textile background, however, it is intended that the invention be used in other applications where it is necessary to forward a twisted strand by a pair of rollers 3 and where the twist will not pass between the rollers but is wiped back instead.

The invention is an adaptation for processing flat yarns by textile machines designed for an over the end takeolf of the yarn.

I claim:

1. A process for longitudinally forwarding a flat unitary filament yarn having a slight twist between the nip of two surfaces turning in opposite directions comprising:

(a) withdrawing a fiat unitary filament yarn over an end of a source package, thereby to impart a slight twist therein; and

(b) passing the yarn more than once between the nip former by two yarn forwarding rolls, one of which has a smooth surface and the other of which has a flat toothed surface to permit the passage of said twisted yarn between the nip without a backing up of the imparted twist toward the package.

2. The process of claim 1 wherein the flat yarn is made from about 7-34 separate filaments of about 10100 mi- UNITED STATES PATENTS 2,077,078 4/1937 Taylor et al 57l57 X 3,148,416 9/1964 Hornbuckle 5791 X 2,953,893 9/1960 Smith et a1 57-36 2,957,300 10/1960 Bahnson 571 3,394,538 7/1968 Neff 579l X 3,402,096 9/1968 Blanchette 57l40 X 3,449,900 6/1969 Eldridge et al. 57--59 3,462,935 8/1969 Brouwer 5734 X 3,488,938 1/1970 Johnson et al 57157 X DONALD E. WATKINS, Primary Examiner US. Cl. X.R. 5 790 

